Nadal, who had his knee taped during his straight-sets loss to Federer in the Shanghai Rolex Masters final on Sunday, said he's suffering from "an over stressing of the knee."

"I sadly announce that I have to pull out of the Swiss Indoors Basel, after seeing my doctor in Spain just after landing from Shanghai," Nadal wrote in a Facebook post. "I am suffering from an over stressing of the knee and the problems where already present at the tournament in Shanghai which now forces me to take a time off on advice of my doctor."

The 16-time Grand Slam champion has not withdrawn from the Paris Masters, which starts on October 30th.